Livestock grazing constrains bird abundance and species richness: a global meta-analysis

BARZAN FLAVIA; BELLIS, LM; DARDANELLI, S.

BASIC AND APPLIED ECOLOGY

ELSEVIER GMBH, URBAN & FISCHER VERLAG

Lugar: ALEMANIA; Año: 2021

1439-1791

Balancing food production and biodiversity conservation is a global challenge today.Livestock grazing is one of the main activities triggering habitat degradation and landuse change around the world. Its effects on biodiversity have been widely explored,with birds being the most studied vertebrates. However, its impact seems to becontradictory given the disparity of the results. To understand the influence of livestockgrazing on birds, we conducted a meta-analysis exploring the effects of several grazingcharacteristics on bird abundance and species richness. Our results showed thatlivestock grazing has a significant negative effect on bird abundance (mean effect size-0.422 ± 0.140), and species richness (mean effect size -0.391 ± 0.141). Livestockgrazing affected negatively the bird abundance in riparian habitats in contrast to theother habitat types. Species richness was negatively affected by grazing in woodyhabitats and Afrotropical and Neotropical regions. Grazing by cattle was moredetrimental for both bird richness and abundance than sheep or a mixture of domesticlivestock grazing. Moreover, intermediate grazing intensity seems appropriate tomaintain bird abundance and richness, as high grazing intensity dropped both birdabundance and species richness substantially, and low grazing intensity reduced birdspecies richness. This pattern supposes a non-linear effect of grazing intensity onbirds. Therefore, the management of grazing intensity and type of livestock could helpto reduce the negative effect on bird abundance and richness, as moderate grazingintensities and mix of livestock types appear to have a minor or null impact on birdabundance and richness. Future studies should explore in-depth the effect of moderategrazing intensities on bird diversity and composition to provide better managementrecommendations to enhance avian conservation in rangelands.